Control units, particularly engine control units, are normally monitored according to a 3-level concept. In this concept, a monitoring module dependent on a function computer plays a central role. The monitoring module monitors a function computer by inquiry-response communication. In this connection, the monitoring module checks whether responses of the function computer are correct and/or whether they arrived at a right time.
Against the background of ever more complex systems having a multitude of control units there exists a need for methods with the aid of which the monitoring of systems of this kind can be implemented safely and with little expense.